Acers, also known as Japanese maples, are trees known for bringing vibrancy into any garden as their unusually-shaped leaves burn with shades of red. If you have an acer tree adorning your garden, then taking proper care of them will ensure that their bold colour remains. One important step in their upkeep is pruning - knowing how and when to prune acers is paramount to keeping the trees happy.
Getting the pruning time wrong can result in weakening this gorgeous gem of a tree, which makes for the perfect addition to a Zen garden idea. And nobody wants that. Which is why we turned to our gardening experts to advise us on what is the perfect time for pruning Japanese maple trees.
When to prune acers
Fun fact, acers are one of the trees that ups the value of your property. So you better not kill yours off, and with it the hundreds of pounds that it could add to your property value.
The aforementioned uniquely beautiful leaves of acers are a good signifier of when to prune the tree. Or rather their absence is as they tend to change colour throughout the seasons and once their dormant period hits, aka winter, they lose that lovely, colourful foliage. That’s the sweet spot of when you should be doing any acer pruning.
‘Here in the UK, you should prune acers during their dormant period, which is generally sometime between November and January,’ advises Steve Chilton, garden expert at LeisureBench. ‘You can also prune them from August to October, but pruning outside of these times can lead to excessive bleeding of their sap, which can weaken the tree and have a distinct negative impact on its health.’
Fiona Jenkins, gardening expert at MyJobQuote.co.uk, adds, ‘After the leaves have fallen it is also easier to observe the shape of the acer and identify branches which should be pruned.’
Just make sure that it’s not absolutely freezing when you’re pruning as that is not ideal for acers either. ‘It's also important not to prune them when temperatures are below 0°C,’ Steve says.
What you’ll need
Product your hands from both tools and hard branches with these tough gloves
Hardy secateurs like these are ideal for pruning small acers or thinner branches
If you're dealing with taller trees and acers with thicker branches, then extendable loppers like these are perfect
How to prune acers
As much as pruning is a key part of acer care, it’s also just as important to know when to stop. As acers can only tolerate light and occasional pruning.
‘Over-pruning is an easy mistake that can happen,’ Jack Sutcliffe, co-founder of Power Sheds, points out. ‘Acer trees do not tolerate heavy or aggressive pruning well. Avoid removing more than a fourth of the foliage of any single branch at once. Over-pruning can stress the tree and lead to slow recovery or even decline.’
Steve is a passionate and knowledgeable garden expert with several years of experience within the field. As the director of LeisureBench, an industry-leading garden furniture company, Steve has developed strong expertise for all things nature and plants.
There is really no need for too much acer pruning at all, as Steve says, ‘Acers are low-maintenance trees, and will only need very occasional pruning. If your tree isn't over-growing then don't prune it. They really don't need excessive pruning as this is likely to damage them.’ We love a low-maintenance tree for an easy garden idea.
He continues, ‘If the tree is healthy, then realistically you'll only need to worry about occasional pruning. This should be done in order to maintain the shape, size and overall aesthetics and appearance of the tree.’
But if your acer tree is in need of pruning, then this is how to do it.
‘When pruning acers look for dead, diseased or damaged wood which should be removed. On mature acers check for crossing branches and thin out any overcrowded branches or those growing inward toward the centre of the tree,’ Fiona explains.
Jack chimes in, explaining why thinning out overcrowded branches is important, ‘If left, they can cause damage when rubbing against each other. To improve airflow and light penetration, selectively remove some branches to thin the canopy.’
FAQs
Can acers be pruned in summer?
It’s not ideal to prune acers in the summer as that results in excessive sap bleeding, which in turn can cause damage to the tree.
‘Avoid pruning in spring or summer as they are prone to sap bleeding which can weaken the tree,’ Jack confirms.
How do I prune my acer to shape?
Depending on the size of your acer, you can use a pair of secateurs, loppers or even a pruning saw if your tree’s branches are particularly thick. Cut any branches growing in the wrong directions or where overcrowding occurs.
‘Take your time, stepping back regularly to check the shape of the tree before proceeding,’ Fiona recommends. ‘Don’t prune more than 25-30% of the tree at any time. Taking too much off the tree can weaken the tree so prune lightly.’
This should ensure that you’re left with a healthy and vibrant, red-leafed maple tree once next spring comes around.
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